modload/main.c

/*
 * Copyright (c) 2008-2014, Pedigree Developers
 *
 * Please see the CONTRIB file in the root of the source tree for a full
 * list of contributors.
 *
 * Permission to use, copy, modify, and distribute this software for any
 * purpose with or without fee is hereby granted, provided that the above
 * copyright notice and this permission notice appear in all copies.
 *
 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
 * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
 * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
 */
 
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
 
#include "elf.h"
 
#define MODULE_FMT "/usr/lib/modules/%s.o"
 
extern void pedigree_module_load(char* file);
extern int pedigree_module_is_loaded(char* name);
int load_module(char* name);
 
int load_module(char* name) {
  // Make the file name
  char* file = (char*)malloc(strlen(name) + strlen(MODULE_FMT) -
                             1);  // -1 because we have -2 (%s) and +1 (\0)
  sprintf(file, MODULE_FMT, name);
  // Try to open the file
  FILE* fp = fopen(file, "r");
  if (fp == NULL) {
    printf("Module file %s not found!\n", file);
    return -1;
  }
  fseek(fp, 0, SEEK_END);
  size_t len = ftell(fp);
  fseek(fp, 0, SEEK_SET);
  // Read the contents of the file
  uint8_t* buffer = (uint8_t*)malloc(len);
  fread(buffer, len, 1, fp);
  fclose(fp);
  // Create the elf structure
  Elf_t* elf = elf_create(buffer, len);
  if (!elf) {
    free(buffer);
    free(file);
    return -1;
  }
 
  // Grab the name and dependencies symbols
  ElfSymbol_t *name_sym = elf_get_symbol(elf, "g_pModuleName"),
              *deps_sym = elf_get_symbol(elf, "g_pDepends");
  if (!name_sym) {
    printf("g_pModuleName symbol not found!\n");
    return -1;
  }
  if (!deps_sym) {
    printf("g_pDepends symbols not found!\n");
    return -1;
  }
 
  char* modname = (char*)elf_relptr(elf, name_sym, *SYM_PTR(elf, name_sym));
  if (pedigree_module_is_loaded(modname)) {
    printf("Module %s is already loaded!\n", modname);
    return -1;
  }
 
  printf("Module %s being loaded...\n", modname);
  uint32_t* deps = SYM_PTR(elf, deps_sym);
  for (size_t i = 0; deps[i]; i++) {
    char* depname = (char*)elf_relptr(elf, deps_sym, deps[i]);
    if (pedigree_module_is_loaded(depname))
      continue;
    if (!load_module(depname) && pedigree_module_is_loaded(depname))
      continue;
    printf("Dependency %s of %s couldn't been loaded!\n", depname, modname);
    return -1;
  }
 
  // Finally load the module
  pedigree_module_load(file);
  if (pedigree_module_is_loaded(modname))
    return 0;
  printf("Module %s couldn't been loaded\n", modname);
  return -1;
}
 
int main(int argc, char** argv) {
  if (argc < 2) {
    printf("Usage: %s <module name>\n", argv[0]);
    return 0;
  } else
    return load_module(argv[1]);
}